Do 45 rpm 12" LPs really sound better than 33 rpm?

I used to produce dance music, and I can tell you that it makes a huge difference in club/DJ music, especially if the final mixdown was to 1/2" 30ips. Not even close, using the same high quality Studer gear (before everything went digital). Thrilling low end, much better headroom. The bottleneck then became mastering, which is so easy to mess up.

It's entirely possible that something in your system, choice of musical genres, or system (or all the above) could make these discs less or more appealing, but personally I cherish my old 45 12s.

There is a Dusty Springfield 12 33/45 you can get. I have it. The Look of Love. One side 33 and the other side 45. I like the 45 side better. 180 gram

Pursuant to chakster’s comments about 7” and 12” being different animals owing to culture etc there is this:

The guy who mastered all the early Byrds singles would ask an LA DJ with the midnight to 6:00AM slot to play demos while he drove around the hills around LA in his convertible GTO to hear what it sounded like, and then make what he felt were the appropriate adjustments for the way the song he felt was most often heard: played by a radio jock and listened to on the car radio, or a portable transistor radio. 

I would not not be surprised that most if not all recording engineers of the late 50s / 60s / early 70s made these kinds of adjustments.